Go with A
I got a Kaufman diamond car hauler, 22'. I have had it for 2.5 years, dragged it on several longer trips 500-600 miles, plus plenty closer (Uwharrie, etc.) I plan to haul it to CO and UT summer after next with the 715 and camper.
2@6k axles, titled at 9990#'s. Brakes both axles. Get the removable fenders, they have to come off to load my 715, only 2 bolts per fender and lift right off. Also the rub rails are well worth what they charge ($100 IIRC), gives you more tie-down options for oddball stuff. Get at least one spare tire. (Twice now, I would have killed for a second spare.) I also got the adjustable coupler....my goal in life is to simply have all my trailer couplers, and all my truck trailer hitches, at the same height.
I got the steel deck. Really hasn't been a problem. Only thing I have to do differently is be more careful when loading up, as I usually load late at night, and gotta be quiet with the chains. A little care, and the neighbors have yet to complain.
I like the slide-in ramps. Of the trailers I used to borrow before I bought, one had tilt-up ramps, and with my 715 loaded, the ramps didn't have room to tilt up w/o hitting the bumper. The other trailer, ramps didn't attach or have a storage space, so they had to go in the back of the pickup. Forgot them once....got a couple of hundred miles from home on a car recovery....no ramps....ever try to find and borrow a set of trailer ramps at 10pm, 4 hours from home???
You can't.
Only downside about the slide-in ramps is they are noisy on a rough road, like the washboard gravel going to the group camp at UNF. I haven't tried it yet, but I think just reaching up underneath and putting a tarp bungee on each one will dampen that.
Anyway, if your trail rig is anything more than a stocker, you won't need ramps to load if it's a dovetail. Just climb on.
Seriously, the only thing I have used the ramps for in the past year is the lawn mower.
Don't get short like 16' if you fabricate, etc...most stock steel comes at 20' or 21'. Plus gives you room to be like yager and put on a camper. You know you want to do it.
edit: Mine weighs right at 2900#. Yes, you pay a price for the few extra feet in length, the rub rails, the steel deck, etc.